Don't load images in collapsed items until they are expanded/needed

[reporter]

My 0.6.1 install has a lot of items with images in them. I'm using the llina theme and have them all collapsed all the time. But the images will still be loaded, anyway, thereby significantly increasing loading times.

My request is a way to not load an item's content (especially external images) until it is expanded (say: needed). Probably the best way to do it is to use Ajax so a full refresh is not necessary. I think this would noticeably reduce the loading times as it would not choke on slow image servers anymore.